A series of experiments are proposed to examine the usefulness of a recently described memory-oriented approach to classical conditioning. In first-order conditioning, this approach maintains that the relative amount of joint rehearsal of the memories of the two stimuli is critical to the formation of an association between the two stimuli and that this stimulus-stimulus association is critical to the acquisition of the conditioned response. The first three experiments will attempt to alter the learning of a "conditioned emotional response" by procedures that should supposedly affect the relative amount of this joint rehearsal; these experiments examine, respectively, forward conditioning, backward conditioning, and the latent inhibition effect. Experiment 4 also uses the latent inhibition procedure but in an attempt to increase rats' learning of a taste-shock association. The last three experiments will examine second-order conditioning of the "conditioned emotional response" and will attempt to determine: if stimulus-stimulus associations are also formed in second-order conditioning, if a rehearsal-like process is involved in second-order conditioning, and if a first-order inhibitory stimulus will suppress the response elicited by a second-order excitatory stimulus if the two stimuli are simultaneously presented.